Spinal implant co-insertion system and method

ABSTRACT

A system and method for substantially simultaneous co-insertion of an implant, such as a cage and plate. An inserter is secured to the cage and plate and is used to hold the components while implanting the components during a surgical procedure.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No. 13/017,622, filed Jan. 31, 2011, which claims priority to provisional U.S. Application Ser. No. 61/300,102, filed Feb. 1, 2010, to which Applicant claims the benefit of the earlier filing date. These applications are incorporated herein by reference and made a part hereof.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to spinal implants and, more particularly, to a co-insertion system and method for substantially simultaneously inserting or implanting a cage and plate in a patient during a surgical procedure.

2. Description of the Related Art

In order to stabilize two adjacent vertebrae of the spine, surgeons will typically place two components. The first is a bone-filled generally cuboidal device, termed a cage, in-between the adjacent vertebrae. The second is a plate device bridging the adjacent vertebrae and attached to the vertebrae via bone screws or similar means. The placement of these two devices is performed in a serial fashion with additive operative time. Additionally, different insertion instruments are utilized for the plate and cage components, resulting in increased cost, complexity and duplication.

Recently, there have been efforts to integrate the plate and cage components into either a unified or mechanically coupled device as exemplified by U.S. Pat. No. 6,235,059, which is incorporated herein by reference and made a part hereof. An advantage of such a unified device is that it creates efficiency for the surgeon by reducing the number of implantation steps and instruments. A disadvantage of such a device is that it doesn't allow for uncoupled motion between the cage and plate components, despite the fact that these components are subjected to differing biomechanical loads after implantation.

What is needed, therefore, is a combination cage-plate device with a co-inserter instrument that allows for loading of both implants on a single inserter and simultaneous co-implantation of separate plate and cage components. The inserter can be removed following implantation resulting in the appropriate positioning of the two independent and uncoupled components.

SUMMARY OF THE INVENTION

One object of the invention is to provide a combination cage-plate device with a co-inserter that allows for substantially simultaneous loading and placement of both the cage and plate on the co-inserter.

Another object of the invention is to provide a system and method for simultaneous co-implantation of the separate plate and cage components of an implant.

Still another object of the invention is to provide an inserter for inserting a cage and plate that can be removed following implementation of the two independent and un-coupled components.

In one aspect, one embodiment of the invention comprises a spinal implant co-insertion system comprising an inserter having a handle and an inserter fastener, a cage having at least one coupler adapted to be fastened to the inserter fastener, and a plate, the inserter being adapted to simultaneously receive the plate and the cage for simultaneous co-implantation of the plate and cage, wherein the inserter fastener comprises at least one of threads, a cam, a key, a spread or a clamp, the at least one coupler of the cage being adapted to be fastened or coupled to the inserter fastener, wherein the plate is not securely coupled or fixed to the cage so that the plate can move, migrate or float with respect to the cage after the plate and the cage are implanted.

In another aspect, another embodiment of the invention comprises a plate for use in a spinal implant co-insertion system, comprising a body, the body having an internal wall that defines a through-hole for receiving an inserter having an inserter end that is screwed into a cage so that the inserter can simultaneously receive the cage and the plate so that they can be simultaneously implanted during a surgical procedure.

In still another aspect, another embodiment of the invention comprises a method for co-inserting a cage and a plate during a surgical procedure, the method comprising the steps of coupling an inserter to the cage and the plate so that the inserter simultaneously receives and supports the cage and plate, simultaneously implanting the cage and plate using the inserter during a surgical procedure, removing the inserter from the cage, and removing the inserter from the plate.

This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the following bullet list and the claims:

-   -   The plate for use in a spinal implant co-insertion system         wherein the internal wall is threaded.     -   The plate for use in a spinal implant co-insertion system         wherein the internal wall is threaded and adapted to threadably         receive a threaded end of the inserter so that the threaded end         may be screwed into both the plate and the cage.     -   The plate for use in a spinal implant co-insertion system         wherein the plate comprises a bone-penetrating prong to         facilitate stabilizing the plate during or following insertion         or when the inserter is removed from the plate and cage.     -   The plate for use in a spinal implant co-insertion system         wherein the plate comprises an aligner for operatively aligning         the cage and the plate together.     -   The plate for use in a spinal implant co-insertion system         wherein the aligner is integrally formed in the plate.     -   The plate for use in a spinal implant co-insertion system         wherein the aligner comprises at least one projection that         causes the plate and cage to become aligned when they are         received on the inserter.     -   The plate for use in a spinal implant co-insertion system         wherein aligner comprises a plurality of projections that cause         the plate and cage to become aligned when they are received on         the inserter.     -   The plate for use in a spinal implant co-insertion system         wherein the plurality of projections cooperate to define a         receiving area for receiving and aligning the cage relative to         the plate.     -   The spinal implant co-insertion system wherein the inserter         fastener is at an end of the inserter.     -   The spinal implant co-insertion system wherein the inserter         fastener comprises threads, a cam, a key, a spread or a clamp,         at least one coupler of the cage being adapted to be fastened or         coupled to the inserter fastener.     -   The spinal implant co-insertion system wherein the inserter         comprises a shoulder to facilitate maintaining the plate and the         cage in a generally adjacent position during a surgical         procedure.     -   The spinal implant co-insertion system wherein the plate         comprises an internal wall that defines a through-hole for         receiving the inserter.     -   The spinal implant co-insertion system wherein the internal wall         is threaded and the inserter fastener is threaded.     -   The spinal implant co-insertion system wherein the plate         comprises an internal wall that defines a through-hole to permit         the end of the inserter to pass.     -   The spinal implant co-insertion system wherein the inserter         fastener are threads and the internal wall is threaded and         adapted to threadably receive the threaded end of the inserter         so that the threaded end may be screwed into both the plate and         the cage.     -   The spinal implant co-insertion system wherein the plate         comprises a bone-penetrating prong to facilitate stabilizing the         plate during or following insertion or when the inserter is         removed from the plate and cage.     -   The spinal implant co-insertion system wherein at least one of         the cage or plate has an aligner for operatively aligning the         cage and the plate together.     -   The spinal implant co-insertion system wherein the aligner is         integrally formed in the plate.     -   The spinal implant co-insertion system wherein the aligner         comprises at least one projection that causes the plate and cage         to become aligned when they are received on the inserter.     -   The spinal implant co-insertion system wherein the aligner         comprises a plurality of projections that cause the plate and         cage to become aligned when they are received on the inserter.     -   The spinal implant co-insertion system wherein the cage         comprises a plurality of aligning apertures for receiving the         plurality of projections in order to align the cage relative to         the plate.     -   The spinal implant co-insertion system wherein the inserter         simultaneously receives the plate and cage so that while the         plate and cage are simultaneously co-implanted, the plate and         cage are coupled together by the inserter and after the plate         and cage are implanted and the inserter is removed from the         plate and cage, the cage and plate are independent, uncoupled         and separate components.     -   The method wherein the first removing step is performed before         the second removing step.     -   The method wherein the method further comprises the steps of         passing inserter through the plate, screwing an end of the         inserter into a threaded opening in the cage so that the plate         becomes mounted on the inserter with the cage securing it to the         inserter.     -   The method wherein the plate and the cage each have a threaded         opening; the method further comprising the step of screwing an         end of the inserter into the threaded opening in the plate and         then into a threaded opening in the cage.     -   The method wherein the method further comprising the step of         aligning the plate to the cage before the inserter is secured to         the cage and plate.     -   The method wherein the method further comprising the step of         aligning the plate to the cage before the inserter is secured to         the cage and plate.     -   The method wherein the method further comprises the step of         packing the cage with graft material before the coupling step.     -   The method wherein the method further comprises the step of         packing the cage with graft material after the coupling step and         before the implanting step.

These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a system for co-insertion of an implant having a cage and plate during a surgical procedure in accordance with one embodiment of the invention;

FIG. 2 is a perspective view showing the system of FIG. 1;

FIG. 3 is an exploded view showing the cage, plate and inserter shown in assembled form in FIGS. 1 and 2;

FIG. 4 is a view showing various details of the plate;

FIG. 5 is another exploded view showing the plate with a threaded aperture for threadably receiving the inserter;

FIGS. 6A and 6B are views of an embodiment showing the inserter traversing a substantial depth of the cage and fastener to a rear wall; and

FIGS. 7A-7C are various fragmentary views illustrating different exemplary embodiments for fastening or coupling the inserter to the cage.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIG. 1, a system and method 10 for substantially simultaneous co-insertion of a cage 12 and plate 14 with an inserter 16 are shown. The system 10 includes the inserter 16 which comprises a grip or first end 16 a and a second end 16 b that is threaded as described later herein.

The inserter 16 further comprises an integral elongated portion 16 c which couples the first end 16 a to the second end 16 b.

The inserter 16 comprises a stop or shoulder 18. As described in more detail later herein, the shoulder 18 (FIG. 3) engages the plate 14 as described later herein.

In the illustration being described and as mentioned, the second end 16 b comprises an inserter fastener 20 which in the illustration being described comprises threads 22. Although the inserter fastener 20 is shown as having threads 22 in the illustration, it should be understood that the inserter fastener 20 could be any suitable means for coupling the inserter 16 to at least one of the cage 12 or plate 14 so that they may be substantially simultaneously mounted on the inserter 16 and implanted into a patient P (FIG. 1) during a surgical procedure. It should be understood that while the illustration described shows a threaded coupling between the cage 12 and inserter 16, a non-threaded fastener, coupler or coupling means may be used. For example, FIG. 7A shows a camming coupling 21 a at the end 16 b with a complementary coupling aperture 21 b in the cage 12. FIG. 7B shows a keying connection 23 a with a complementary keying coupling aperture 23 b. FIG. 7C shows a spreading or clamping coupling 25 a at end 16 b and a complementary spreading or clamping aperture 25 b.

For ease of illustration, FIG. 1 shows the inserter 16 being used to substantially simultaneously insert the cage 12 and plate 14 into the patient such that the cage 12 becomes situated between a first vertebra 24 and a second vertebra 26 as illustrated. In the illustration being described, at least one or a plurality of screws 28 may be received in at least one aperture 40 and 42 of the plate 14 and screwed into, for example, the first vertebra 24 in a manner conventionally known in order to secure the plate 14 thereto. In the illustration, the plate 14 is not secured, coupled or fixed to the cage 12 and can move, migrate or float with respect thereto. The cage 12 and plate 14 are separate components.

Referring now to FIGS. 2 and 4, note that the cage 12 comprises a plurality of apertures 30 through which a graft material 15 (FIG. 1) may be inserted or packed into the cage 12. The cage 12 further comprises at least one coupler 32. In the illustration being described, the at least one coupler 32 has a threaded cage wall 32 a that defines a threaded opening 34 for receiving the threads 22 of the inserter 16 as illustrated in FIGS. 1-3. The at least one coupler 32 and inserter fastener 20 may be any suitable means or method for affixing a portion, such as the second end 16 b, of the inserter 16 to the cage 12 after the inserter 16 has received the plate 14. While the illustration being described illustrates that the inserter fastener 20 is at the second end 16 b of the inserter 16, it should be understood that it does not necessarily have to be on the second end 16 b, and it could be situated at other locations on the inserter 16.

Referring back to FIG. 3, note that the cage 12 further comprises at least one or a plurality of aligning walls 36 that define at least one or a plurality of aligning apertures 38 as shown. The function and operation of the at least one or a plurality of aligning apertures 38 will be described later herein.

Referring now to FIG. 3, note that the plate 14 comprises a first side 14 a and a second side 14 b as shown. The plate 14 is adapted or configured to define a plurality of screw receiving openings or apertures 40 and 42 which have an associated integral lock 44 and 46, respectively. The operation of the integral lock is similar to that described in U.S. Pat. Nos. 7,182,782; 7,641,701; 7,655,028 and U.S. Patent Publications 2006/0195100; 2007/0123885; 2008/0021476 and 2010/0145453, all of which are incorporated herein by reference and made a part hereof. Features of the plates in those references may also be used in the embodiments being described.

The plate 14 has an internal wall 48 that defines a through-hole 50 for receiving the second end 16 b of the inserter 16. In the illustration shown in FIG. 3, the through-hole 50 is not threaded and is sized to permit the threads 22 of inserter 16 to pass through the through-hole 50. In this regard, the second end 16 b of the inserter 16 has a shank or elongated portion 25, a portion of which comprises the threads 22 and an unthreaded portion 23 as illustrated in FIG. 3. In the illustration being shown in FIG. 2, the internal wall 48 becomes operatively associated with the unthreaded portion 23 after the second end 16 b is inserted in the through-hole 50 as shown.

As shown in FIGS. 3 and 5, the plate 14 may further comprise a receiving shoulder 52 for receiving the stop or shoulder 18 so that the plate 14 does not ride along an unthreaded shank portion or end 16 d of the inserter 16.

As illustrated in FIGS. 3 and 5, the second end 16 b is inserted through the through-hole 50 of the plate 14 and then screwed into the threaded opening 34 so that the plate 14 becomes secured between the stop or shoulder 18 and the cage 12 as shown. Once the cage 12, plate 14 and inserter 16 are secured together, the inserter 16 may be used to position the cage 12 between the first vertebra 24 and the second vertebra 26 and held in place while at least one screw 28 is received in the at least one aperture 40 and 42 and screwed into bone. After the plate 14 and cage 12 are operatively positioned and secured to the bone, the inserter 16 is unscrewed from the cage 12 and withdrawn from the plate 14 and the patient.

In one embodiment and in order to maintain the relationship of the cage 12 to the plate 14 during insertion, at least one of or both of the cage 12 or plate 14 may comprise at least one or plurality of aligners 54 and 56 (FIG. 4). The at least one or plurality of aligners 54 and 56 are integrally formed in the plate 14 as shown. The at least one or plurality of aligners 54 and 56 are received in the aligning apertures 38 and cause the plate 14 to be generally aligned with the cage 12 after the inserter 16 receives the plate 14 and cage 12. Of course, other means for aligning the plate 14 relative to the cage 12 may be provided.

The at least one or plurality of aligners 54 and 56 facilitate aligning the cage 12 to the plate 14 and also facilitate preventing the plate 14 or cage 12 from any rotational movement when the inserter 16 is unscrewed or dismounted from the cage 12 and plate 14. In the illustration being described, the at least one or plurality of aligners 54 and 56 are integral projections that extend away from surface 14 b as shown in FIGS. 4 and 5.

FIG. 5 illustrates another embodiment wherein the plate 14 comprises an internal threaded wall 60 as shown. In this embodiment, the second end 16 b of the inserter 16 has threads 22 that are long enough to screw into both the plate 14 and the cage 12 to threadably secure the cage 12 and plate 14 together.

Although the embodiments being shown and described herein illustrate various means for securing the cage 12 and plate 14 together using the threads 22 that are threadably received in at least one or both of the cage 12 and plate 14, other means for securing the inserter 16 to the cage 12 and plate 14 may be used without departing from the true spirit and scope of the invention.

The system and method 10 for co-inserting the cage 12 and plate 14 into the patient during a surgical procedure will now be described. In general, the end 16 d of the inserter 16 is passed through the through-hole 50 and then screwed into the threaded opening 34 in the cage 12. Note that if the embodiment of FIG. 5 is used, then the threaded second end 16 b of the inserter 16 is screwed first into the internal wall 48 of the plate 14 and then into the threaded opening 34 of the cage 12 to secure the cage 12 and plate 14 to the inserter 16. In either embodiment, the stop or shoulder 18 is received in the receiving shoulder 52 of the plate 14.

The inserter 16 substantially simultaneously receives and supports the cage 12 and plate 14 so that simultaneous implanting of the cage 12 and plate 14 using the inserter 16 can be performed during a surgical procedure. In this regard, note in FIG. 1 that the co-insertion system 10 enables the cage 12 and the plate 14 to substantially simultaneously be positioned such that the cage 12 is received in the area between the vertebra 24 and vertebra 26.

After the cage 12 and plate 14 are positioned, the inserter 16 may be unscrewed or rotated and removed from the cage 12 and plate 14. In this regard, note that the inserter 16 may be held in place while at least one of the plurality of screws 28 is used to secure the plate 14 to at least one of the vertebra 24 or 26. Thereafter, the inserter 16 may be unscrewed from the cage 12 and/or plate 14. It should be understood, therefore, that the inserter 16 is first removed from the cage 12 and then removed from the plate 14 at the end of the surgical procedure. In contrast the inserter 16 is inserted first through the plate 14 and then into the cage 12 when the inserter 16 is mounted to these components.

As alluded to earlier herein, when the inserter 16 is mounted to the cage 12 and plate 14, the at least one or plurality of aligners 54 and 56, may be used to align and maintain alignment of the cage 12 and plate 14 together.

Advantageously, the system and method 10 enable the co-insertion or substantially simultaneous insertion of the cage 12 and plate 14 using a single tool, namely, the inserter 16. In a preferred embodiment, the cage 12 is first packed or loaded with the graft material 15 (FIG. 1) either before or after the plate 14 and cage 12 are mounted on the inserter 16. Alternatively, the graft material 15 may be inserted or packed into the cage 12 after it is positioned in the patient.

Other features may include:

-   -   1. At least one or a plurality of bone-penetrating prongs (not         shown) may be situated on the second side 14 b of the plate 14         to penetrate the bone and facilitate stabilizing the plate 14         during or following insertion or when the inserter 16 is removed         from the plate 14 and cage 12.     -   2. Note that the at least one or plurality of aligners 54 and 56         are illustrated as being integral with the plate 14, other types         of aligners could be used and/or the aligners could be situated         on or even integral with the cage 12, with the plate 14 being         adapted to receive the at least one or plurality of aligners 54         and 56, such as by providing receiving apertures in the plate         14.     -   3. Another feature of the system and method 10 described herein         is that it facilitates or enables implantation of two         independent and un-coupled components, namely the cage 12 and         plate 14. In this regard, even if the components comprise an         aligner, the cage 12 and plate 14 are not coupled directly         together in the illustrations being described. It is envisioned         that this feature of the plate 14 relative to the cage 12 can be         provided similar to that which is shown in U.S. Pat. No.         7,182,782, which is owned by the Assignee of the present         application and which is incorporated herein by reference and         made a part hereof.     -   4. The plate 14 may be comprised of a shortened length plate 14         which does not extend past the upper and lower borders of the         cage 12.     -   5. The plate 14 may incorporate various screw-plate locking         mechanisms to prevent rotation and/or expulsion of fixation         screws 28.     -   6. The plate 14 may comprise various screw arrangements and/or         angulations, such as one upward screw 28 or downward screw         alone; one upward and one downward; two upward and one downward;         one upward and two downward; or two upward and two downward or         the like.     -   7. The cage 12 may comprise a reduced, fenestrated or eliminated         front wall, such that the inserter 16 can transverse the plate         14 and a substantial depth of the cage 12 with the inserter 16         engaging a rearward wall 12 a of the cage 12. This feature is         illustrated in FIGS. 6A and 6B and shows the inserter 16         traversing the depth of the cage 12 so that it can fasten to a         rear wall 12 a of the cage 12 as shown.     -   8. The inserter 16 to cage 12 mechanical coupling may         incorporate various fixation means mentioned earlier, such as         threading, camming, keying, spreading, clamping and otherwise         reversibly locking the inserter 16 to the cage 12.

In the illustrations, the components can be made from any biocompatible material. Potential biocompatible materials comprise metals (for example, titanium), metal alloys (for example, titanium alloy), carbon fibers, composites, polymers or hybrid materials.

This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the Summary of the Invention and the claims.

While the system and method herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise system and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims. 

What is claimed is:
 1. A spinal implant co-insertion system comprising: an inserter having a handle and an inserter fastener; a cage having at least one coupler adapted to be fastened to said inserter fastener; and a plate; said inserter being adapted to simultaneously receive said plate and said cage for simultaneous co-implantation of said plate and cage; wherein said inserter fastener comprises at least one of threads, a cam, a key, a spread or a clamp, said at least one coupler of said cage being adapted to be fastened or coupled to said inserter fastener; wherein said plate is not securely coupled or fixed to said cage so that said plate can move, migrate or float with respect to said cage after said plate and said cage are implanted.
 2. The spinal implant co-insertion system as recited in claim 1 wherein said inserter fastener is at an end of said inserter.
 3. The spinal implant co-insertion system as recited in claim 2 wherein said inserter fastener comprises threads, a cam, a key, a spread or a clamp, at least one coupler of said cage being adapted to be fastened or coupled to said inserter fastener.
 4. The spinal implant co-insertion system as recited in claim 1 wherein said inserter comprises a shoulder to facilitate maintaining said plate and said cage in a generally adjacent position during a surgical procedure.
 5. The spinal implant co-insertion system as recited in claim 1 wherein said plate comprises an internal wall that defines a through-hole for receiving said inserter.
 6. The spinal implant co-insertion system as recited in claim 5 wherein said internal wall is threaded and said inserter fastener is threaded.
 7. The spinal implant co-insertion system as recited in claim 3 wherein said plate comprises an internal wall that defines a through-hole to permit said end of said inserter to pass.
 8. The spinal implant co-insertion system as recited in claim 7 wherein said inserter fastener are threads and said internal wall is threaded and adapted to threadably receive said threaded end of said inserter so that said threaded end may be screwed into both said plate and said cage.
 9. The spinal implant co-insertion system as recited in claim 1 wherein said plate comprises a bone-penetrating prong to facilitate stabilizing said plate during or following insertion or when said inserter is removed from said plate and cage.
 10. The spinal implant co-insertion system as recited in claim 1 wherein at least one of said cage or plate has an aligner for operatively aligning said cage and said plate together.
 11. The spinal implant co-insertion system as recited in claim 10 wherein said aligner is integrally formed in said plate.
 12. The spinal implant co-insertion system as recited in claim 11 wherein said aligner comprises at least one projection that causes said plate and cage to become aligned when they are received on said inserter.
 13. The spinal implant co-insertion system as recited in claim 10 wherein said aligner comprises a plurality of projections that cause said plate and cage to become aligned when they are received on said inserter.
 14. The spinal implant co-insertion system as recited in claim 13 wherein said cage comprises a plurality of aligning apertures for receiving said plurality of projections in order to align said cage relative to said plate.
 15. The spinal implant co-insertion system as recited in claim 1 wherein said inserter simultaneously receives said plate and cage so that while said plate and cage are simultaneously co-implanted, said plate and cage are coupled together by said inserter and after said plate and cage are implanted and said inserter is removed from said plate and cage, said cage and plate are independent, uncoupled and separate components.
 16. A plate for use in a spinal implant co-insertion system, comprising: a body; said body having an internal wall that defines a through-hole for receiving an inserter having an inserter end that is screwed into a cage so that said inserter can simultaneously receive said cage and said plate so that they can be simultaneously implanted during a surgical procedure.
 17. A method for co-inserting a cage and a plate during a surgical procedure, said method comprising the steps of: coupling an inserter to the cage and the plate so that said inserter simultaneously receives and supports said cage and plate; simultaneously implanting the cage and plate using the inserter during a surgical procedure; removing said inserter from said cage; and removing said inserter from said plate.
 18. The method as recited in claim 17 wherein said first removing step is performed before said second removing step.
 19. The method as recited in claim 17 wherein said method further comprises the steps of: passing inserter through said plate; screwing an end of said inserter into a threaded opening in said cage so that said plate becomes mounted on said inserter with said cage securing it to said inserter.
 20. The method as recited in claim 17 wherein said plate and said cage each have a threaded opening; said method further comprising the step of: screwing an end of said inserter into said threaded opening in said plate and then into a threaded opening in said cage.
 21. The method as recited in claim 17 wherein said method further comprising the step of: aligning said plate to said cage before said inserter is secured to said cage and plate.
 22. The method as recited in claim 20 wherein said method further comprising the step of: aligning said plate to said cage before said inserter is secured to said cage and plate.
 23. The method as recited in claim 17 wherein said method further comprises the step of: packing said cage with graft material before said coupling step.
 24. The method as recited in claim 17 wherein said method further comprises the step of: packing said cage with graft material after said coupling step and before said implanting step. 